Headsets generally include a headband that incorporates, or is made from, a spring, which passes over the head of the user and presses the ear cups to the wearer's head with some predetermined force. Some mechanism is provided to allow the length of the headband to change, such as providing a headband element having a hollow cavity therein, which cavity receives sliding elements, which are attached to the ear cups. The headband also provides vertical support to keep the ear cups from slipping off the wearer's ears under the influence of gravity or other G forces.
The tension supplied by the headband is in the form of a bending moment transmitted along the components of the headband. If the material of the headband, the stress, and bending moment are nearly constant, the only variables which remain are the width and thickness of the band. However, as the headset is adjusted for different wearers, or as a single wearer changes the location of the headset on the wearer's head, the moment changes, as the distance between the headband element and the ear cup changes. While it is desirable to provide a constant, evenly disbursed headband-generated force on the ear cups, changing the bending moment of the headband changes the lateral force applied by the headband in prior art systems.
Another feature of aircraft headsets is noise reduction so that a headset wearer (1) can hear sound generated by transducers in the ear cups over the aircraft background noise, which is accomplished by providing an acoustic seal between the wearer's head and the ear cup; and (2) generate a signal from a microphone, usually attached to one of the ear cups, wherein the background noise from the aircraft is minimized by the microphone pickup. The present invention embodies an improved headphone ear seal that further improves comfort while providing a good
Prior art cushions have incorporated a variety of non-liquid gelatin-like material on a ring of soft, slow recovery foam enclosed within a thin stretchable layer of polyurethane skin. A variety of configurations have been used, including multiple rings of cushioning, various thicknesses and durometer ratings of material, etc. The known prior art has presented cushions of uniform cross-section, while failing to consider the shape of the human head.
Likewise, microphone pickups have used a variety of dampening materials to eliminate pickup of vibrations from the headset and to reduce wind and pop noises. These systems have generally placed sound-dampening materials outside the microphone housing, and have proven less than adequate.